1. Perl
Functions

2. Defining Functions sub subroutine_name { stmt1; stmt2; … }
Arguments are not listed in declaration
May use a return statement
If no return statement, value of last expression is returned
Can return scalar, array, or hash

3. Calling Functions Called by
sub_name(arg1, arg2, …);
Parens may be omitted if declaration has already been seen
Arguments are available in called function as entries in

4. Sample Function sub max { ($a, $b) = @_; $a > $b ? $a : $b; }
Puts args into variables
Returns larger if they are numbers

5. Array and Hash Arguments
Can only pass one array or hash as an argument unless you know the size
Args are flattened
@b) #all
Can precede array or hash by a fixed number of scalars but
$c)
won’t work

6. Scope
my($a); my
Declares local variable with scope of block (including function) or loop (in control
Parentheses are optional

7. Strict use strict; Directive requires Declare all variables
Declare all functions before first use